Hybrid Telemetry System for Drilling Operations

ABSTRACT

A system of installing a telemetry cable in a drill string, the drill string comprising a plurality of drill pipe sections, the drill string having a drill pipe electrical connector at the bottom of the drill string, an electrical wireline capable of carrying an electric signal is disposed in the drill string, terminating in a lower wireline electrical connector capable of connecting with the lower drill pipe electrical connector, and an upper termination block.

The present invention relates to a telemetry system, in particular, onedisposed in a drillpipe.

The conventional manner of drilling a borehole comprises lowering adrill bit into the earth, the drill bit being powered, for instance, bythe rotation of the drillpipe, or by fluids circulating through thedrillpipe and thence back up to the surface through the space betweenthe drillpipe and the borehole. The drillpipe is made up of sections,new sections being added periodically at the top of the drillpipe stringto allow the drill bit to be lowered further.

Much useful data can be garnered from sensors included in the drillpipe,such as temperature and pressure. To retrieve this information at thesurface requires some form of media to transmit it through. Knownsystems include using pressure waves through the circulating mud, andelectromagnetic pulses. Better rates of transfer and less attenuationmay be achieved however by using an electrical conducting element.

The simplest way of installing a conducting cable, or indeed any line,along the drillpipe string is to wait until drilling has ceased andlower a single length down the drillpipe string. Where it is necessaryto take readings from instrumentation means before the drillpipe iscompleted however, the cable must be lowered into the drillpipe string,only to be withdrawn each time a new drillpipe section is added to thedrillpipe string.

One known method comprises a drillpipe incorporating conductingelements. The conducting elements of adjoining sections of drillpipe areelectrically connected by inductive couplings, Such a system isexpensive, and requires signal boosts. Many telemetry systems rely upona segmented cable running through the drillpipe, cable sections beingadded in order to allow fresh sections of drillpipe to be added.

Every connection between individual lengths of cable provides a furtheropportunity for faults to occur.

The object of the present invention is to provide an apparatus andmethod for disposing reliable telemetric equipment in drillpipes and thelike in an efficient manner.

According to the present invention, there is provided a system ofinstalling a telemetry cable in a drill string as defined in claim 1.

This advantageously allows the maximum length of cable is installedinside the drillpipe with an electrical wet connector at each end. Thecable may be prepared offsite, terminated and tested to a requiredlength with a small adjustable length section (up to 40 ft) so rapidinstallation is possible. The upper termination of the cable is in aside pocket of a tool joint, the tool joint can also include sensorssuch as pressure and temperature.

As the new hole is drilled, wired drillpipe can then be added, tocommunicate from the wireline terminating at the tool joint to surface.

Preparing the cable offsite, terminated and tested to a required lengthwith a small adjustable length section (up to 40 ft) allows rapidinstallation. The upper termination of the cable may be in a side pocketof a tool joint, the tool joint can also include sensors such aspressure and temperature.

As new hole is drilled, a second wireline may be installed from the tooljoint to the top of the added drillpipe, the wireline is allowed to forma loop inside the drillpipe, the upper end of the wireline has a one wayanchor, a electrical termination and acoustic transmitter/receiver.

Inside the riser or BOP stack, whichever is below the first 40 ft of rigfloor, a line of acoustic transmitters and recievers may be included,which listen and transmit to the acoustic transmitter/receiver of thewireline anchored inside the drill pipe.

As new drillpipe is added the wireline acoustic transmitter is fishedand anchored to the top of the new drillpipe added, this may be repeateduntil the wireline can accommodate no new drillpipe. At this time a newsensor sub is installed in the drillpipe and the wireline electricaltermination docked into the sensor sub.

A telemetering system will now be described, by way of example, withreference to the drawings, of which;

FIG. 1 shows a section side view of a cased drilled hole, with newdrillpipe and drilling assembly installed, with a side pocket electricaltermination tool joint fitted at the rig floor. Adjacent to the well isa pre-assembled/terminated wireline of approximately a similar length.

FIG. 2 shows a similar view to FIG. 1 with the pre-assembled wirelineinstalled inside the drill pipe, the lower wet connector terminationconnected to its mating connector in the drilling assembly, at thesurface is a means of rapidly hanging off a pre-assembled terminatedcable.

FIG. 3, shows in more detail the surface termination hang of sequence.

FIG. 4 shows a subsequent step in the surface hang off sequence, thecable termination is lowered and installed into the tool joint sidepocket connector, surplus cable is applied to hang from the cabletermination and a cable termination block, the hanging weight of thecable is supported by a disposable support line.

FIG. 5 shows a subsequent step in the hang off sequence to FIG. 4, whilethe hanging weight of the cable inside the drillpipe is still supporteda sliding support is lowered down the cable and comes to rest on top ofthe upper electrical termination. It is then locked to the remainingsupporting cable inside the drillpipe. The surplus support cable is thencut and removed so that new drillpipe can be added.

FIG. 6 shows a similar view to FIG. 5 with a joint of wired drillpipeadded. This allows the rig to drill new hole and supply fast data to therig floor.

FIG. 7 shows an overview of the hybrid telemetry system, with internalwireline from the drilling assembly to the side pocket tool joint andthen wired drillpipe back to surface.

FIG. 8 shows a schematic of the side pocket tool joint, incorporating asensor package to measure annulus measurements such as pressure andtemperature.

FIG. 9 shows an alternative embodiment of the hybrid telemetry systemshown in FIG. 7, with two sets of internal wireline being used, one fromthe drilling assembly to the side pocket tool joint, and then a furthersection of internal wireline, this being connected to a wired drillpipeback to surface.

FIG. 10 shows a further embodiment, with a second wireline installed ina second wet connector of the sensor sub, and the wireline forming a Uloop, its upper end has a one way anchor which holds the upper assemblywhere it is pulled up to by a retrieval mechanism, the upper assemblycomprises a electrical termination and an acoustic transmitter/receiver.

FIG. 11 shows a similar view to FIG. 10 with the retrieval mechanismremoved and a new joint of drillpipe added.

FIG. 12 shows side view of the well in the embodiment of figure fromsurface to total depth, at surface it shows the acoustic transmitterinside the drillpipe talking to a series of acoustictransmitters/recievers inside the riser or BOP stack

FIG. 13 show a similar view to FIG. 12 with the drillpipe in a lowerposition.

FIG. 14 is a similar view to FIG. 13, the drillpipe is at its lowestposition before a new joint can be added, the retrieval mechanism fishesthe one way anchor and takes it to the top of the drillpipe.

FIG. 15 is a similar view to FIG. 14, the wireline inside the drillpipecan no longer accommodate new drillpipe to be added, so has to beterminated in a sensor sub.

FIG. 16 is a similar view to FIG. 15 with a new wireline added anddocked into the sensor sub to link all the wirelines to its uppertermination. Its upper termination includes the previously mentionedelectrical termination, anchor assembly and acoustictransmitter/receiver.

FIG. 17 is a similar view to FIG. 16 with a new joint of drillpipeadded.

FIG. 18 is a more detailed side section view of the sensor sub of FIG.10, with electrical terminations of a lower and upper wireline.

Referring to the figures in more detail, embodiments of the inventionwill be described.

FIGS. 1 to 7 there is shown a borehole 1, lined by a casing 2 which hasbeen cemented in place, a rig floor is shown as 3. A drilling assembly 4consisting of a directional drilling system 5, steering and sensorpackage 6 is lowered into the well on drillpipe 7, when it has reachedthe bottom of the well 8 a side pocket tool joint 9 is installed intothe drillstring, the total length of the drill string would be known towithin a +/−5 to 10 feet. A off-site prepared wireline 10 with upper andlower terminations is lowered into the inside of the drillpipe, itslower end has a wet electrical connector termination 11, this lands anddocks into a mating termination on top of the telemetry module of thesensor package 6. At surface, surplus cable has to be accommodated intothe drillpipe. This is achieved as follows; the wireline is terminatedinto a termination block 12 at a known shorter length of the drillpipe.The hanging weight of the wireline is supported from the terminationblock 12 by a suitable strong cable 13. The wireline 15 is first slackedoff, so that it rests in a helical path 15′ on the inside of thedrillpipe. A flexible lighter gauge Kevlar braided cable 14 continuesthe wireline 15′ signal transmission capability to a upper electricaltermination 16. The upper termination can be lowered and docked into aninternal side pocket electrical connector 17, the surplus cable 13 isallowed to hang from the docked connector 18 forming a U shape to thetermination block 12. A cable clamp and support 19, is lowered down thesupport cable 13 and locates into the top of the cable termination 16,and locks the two items 16, 19 into the side pocket. The cable clamp 19locks onto the support cable 13 at 20. The remaining or disposablesection of support cable 22 can be removed by cutting at 21.

Allowing the surplus cable of the wireline 15′ to adopt a helical shapecauses the wireline 15′ to abut against the inner surface of thedrillpipe sections making up the drillstring. The friction of thisabutment supports the weight of the wireline, meaning that less strainis placed on the wireline during installation.

Now new drillpipe 23 can be added to drill new hole, the new drillpipebeing wired drillpipe having conductors within the drillpipe sectionwalls and electrical connectors at the joints of each drillpipe section,so that a conductive path is established along multiple drillpipesections.

Additionally, these wired drillpipe sections can have sensors within thedrillpipe to gather telemetry which is them transmitted through theconductive path. This is well understood equipment and availablecommercially as Intellipipe®. In this way, a fast cost effectivetelemetry path is established from the drilling assembly to surface, butavoiding the cost of using wired drillpipe sections over the entirelength of the drillpipe string.

FIG. 8 shows a side pocket docking port with annular sensor capability.The electrical termination of the wireline goes to an inductive coil 30,which transmits the signal across the tool joint via contactlesstelemetry to a coil 31 in the upper tool joint. A sensor package 32could measure annular parameters such as pressure, temperature etc., andthese too could be processed and transmitted back to surface, providingvital information of what is happening in the wellbore annulus.

Referring to FIG. 9, the hybrid telemetry system may use more than onesection of internal wireline, allowing greater lengths of conventional,non-wired drillpipe section to be used. Here, a first wireline 15′ anddocked connector 28 is disposed between the drilling assembly and aninternal side pocket 27. A clamp connector 30 is then deployed in thesame manner as the clamp 20 shown in FIG. 7. In this embodiment however,the clamp connector 30 includes a second wireline 25 extending from it,and the clamp connector 30 makes an electric connection with the dockedconnector 28.

Further conventional drillpipe sections can then be added, with thewireline 25 suspended by a support line (not shown) and threaded throughnew drillpipe sections as they are added in a similar manner to thatdescribed in relation to FIGS. 1 to 7. The second wireline 25 is thenconnected to a docking connector 38 with a clamp 39 in exactly the samemanner as described in to FIGS. 1 to 7, the docking connector 38 havingan electrical connection to a conductor running through the drillpipesection added above this, such as drillpipe sections of the Intellipipe®design.

Lengths of conventional drillpipe sections and lengths of wireddrillpipe sections can in this way be alternated depending on where theoperators what wired drillpipe telemetry, so that the cost of using thewired drillpipe sections is minimised and reliability and speed ofinstallation is increased.

The upper termination block of the wireline has been described asdocking with a side pocket connector, where a side pocket is usuallyconsidered to be a cavity in a drillpipe section communicating with theinner bore of the drillstring, but which does not occlude the innerbore. However, though less ideal, the drill pipe connector could alsosecured to the drill pipe in some manner so that the connection of thetermination block of the electrical wireline can be made to theconnector attached to the drill pipe section (whether as a wired drillpipe section, or in order to continue the drill pipe telemetryconnection in a ‘daisy chain’ manner). The drill pipe connector couldfor example be secured to the inner surface of the drill pipe, or couldcomprise a spider that spans the throughbore of the drill pipe section.It will though be accessible from the rig floor as the drillpipe sectionis added so the connection between the wireline and the drillpipeelectrical connector can be made.

In an alternative embodiment, additional features can be included at thehanging off stage. Referring to FIGS. 10 to 17, the method previouslydescribed in relation to FIGS. 1 to 5 is carried out. Then a newwireline with a side pocket electrical connector 30 is disposed tobecome a new extension of the wireline end termination 18 hanging off inthe electrical connector 17, the upper end of this cable has a one wayanchor 31, below which is connected the wireline electrical termination32. Just before a new section of drill pipe 33 is added, a fishing tool34 is lowered inside the drillpipe and pulls the one way anchor toaround the rig floor level 35. It is disengaged and the drillpipe 33 isconnected to the drillpipe in the slips, and drilling ahead cancommence. As the drillpipe goes below the rig floor, the acoustictransmitter/receiver 36 is continuously transmitting to an array ofacoustic transmitter/recievers 37 either mounted in the riser or the BOPstack. Many joints of drillpipe can be added, because there is an excessof extra wireline 38 forming a U shape inside the drillpipe. As the topof the drillpipe reaches the rig floor, the fishing tool again goesinside the drillpipe and fishes the one way anchor 39 to just below therig floor. When there is insufficient wireline to add new drillpipe, asensor sub 40 and wire termination is added. This allows the lastwireline 41 to be terminated and a new wireline 42 to be added with atermination 43 into the sensor sub and a one way anchor and transmitter44 at its upper end. The sensor sub could measure external pressure andtemperature and be useful for both well control and gather other welldata. The wireline is in effect daisy chained together in controlledlengths and joined together at each sensor sub using electricalconnectors.

So a fast cost effective telemetry path is established from the drillingassembly to surface.

FIG. 18 shows a side pocket docking port with annular sensor capability.The wireline electrical termination 50 of the wireline plugs into amatching electrical connector 51 this goes to a sensor module 52 whichconverts the sensor signals to a telemetry signal and transmits thatonto the wireline. A second connector 53, allows a new wireline 54 to beadded to extend the wireline inside the drillpipe and its endtermination 55 plugs into the matching terminator 53 in the sensor sub.The sensor package 52 could measure annular parameters such as pressure,temperature etc, and these too could be processed and transmitted backto surface, providing vital information of what is happening in thewellbore annulus.

1.-18. (canceled)
 19. A system of installing a telemetry cable in adrill string, the drill string comprising a plurality of drill pipesections, the drill string having a drillpipe electrical connector at alower position of the drill string disposing an electrical wirelinecapable of carrying an electric signal in the drill string, terminatingin a lower wireline electrical connector capable of connecting with thelower drill pipe electrical connector, and an upper terminationconnector, the length of the electric wireline being greater than thelength of the drill string between the lower position of the drillstring and the rig floor at the time the electrical wireline is disposedin the drill string connecting the lower wireline electrical connectorand the lower drill pipe electrical connector the drill string having adrillpipe section electrical connector on inner surface of a drill pipesection at the top of the drill string docking and securing the upperelectrical termination connector of the electrical wireline to thedrillpipe section electrical connector adding a subsequent drill pipesection to the top of the drill string.
 20. A system of installing atelemetry cable according to claim 19, wherein upper electricaltermination is secured in the drillpipe section electrical connector bya clamp member lowered through the drill pipe section added to the topof the drill string.
 21. A system of installing a telemetry cableaccording to claim 20, wherein the cable clamp is slidably mounted onthe support cable while being lowered
 22. A system of installing atelemetry cable according to claim 19, wherein the surplus support cableis cut when a new drill pipe section is added to the drill string.
 23. Asystem of installing a telemetry cable according to claim 19, whereinthe drillpipe section electrical connector is then connected to a secondlength of wireline disposed in the inner bore of the drillpipe.
 24. Asystem of installing a telemetry cable according to claim 19, whereinthe drillpipe section electrical connector is connected to a conductorformed in the inner wall of the drillpipe section immediately above thepocket electrical connector.
 25. A system of installing a telemetrycable according to claim 19, wherein the lower position of the drillstring is the drilling assembly.
 26. A system of installing a telemetrycable according to claim 25, wherein the drilling assembly includessensors connected to the drillpipe electrical connector.
 27. A system ofinstalling a telemetry cable according to claim 24, conductor formed inthe inner wall of the drillpipe section includes or is connected tosensors attached to the drillpipe section.
 28. A system of installing atelemetry cable according to claim 19 wherein a support cable isattached to the electrical wireline to support the weight of theelectrical wireline while a new drillpipe section is added to thedrillstring.
 29. A system of installing a telemetry cable according toclaim 19 wherein the surplus cable of the length of the electricwireline is disposed in the substantially helical manner.
 30. A systemof installing a telemetry cable according to claim 19 wherein thedrillpipe section electrical connector is situated in a side pocket onthe drill pipe section.
 31. A system of installing a telemetry cableaccording to claim 19 wherein a one way anchor is included at the upperend of the electric wireline.
 32. A system of installing a telemetrycable according to claim 31, wherein a fishing tool is used to pullanchor up when a new drillpipe section is added.
 33. A system ofinstalling a telemetry cable according to either claim 31, wherein theanchor includes a sensor.
 34. A system of installing a telemetry cableaccording to claim 33, wherein the sensor includes a wirelesstransmitter.
 35. A system of installing a telemetry cable according toclaim 19 wherein a sensor included at termination connection ofwireline.
 36. A system of installing a telemetry cable according toclaim 19 wherein the side pocket docking connection includes a sensor.